Delaware Chancery Judge Leo Strine Jr. ruled that Raleigh, N.C.-based Martin Marietta had violated a confidentiality agreement with Vulcan when it prepared a bid for Vulcan, and he blocked Martin Marietta from pursuing the takeover attempt for four months.

The ruling appears to basically postpone Martin Marietta's bid for Vulcan until next year, because Vulcan shareholders will be selecting new board members at a meeting on June 1. Martin Marietta had advanced its own dissident slate of candidates for the board.

"We appreciate the Delaware Chancery Court's careful consideration of this matter and are pleased with the decision," Vulcan said in a statement released this afternoon.

Vulcan has resisted Martin Marietta's hostile takeover bid since it was launched on Dec. 12. The initial offer was valued at $4.7 billion and has since risen to $5.5 billion. Vulcan has repeatedly said the offer is inadequate.

Strine's ruling follows a trial where Vulcan had alleged that Martin Marietta had breached a confidentiality pact agreed to when the two companies were involved in long-running, friendly merger talks. Vulcan walked away from those negotiations, and Martin Marietta replied with an unsolicited offer.

"Martin Marietta breached the procedural obligations to which it remained subject," Strine said in a 139-page opinion, according to Bloomberg.

Bloomberg reported that Martin Marietta said it is reviewing the ruling and considering its options.

A lot is at stake for Vulcan and Birmingham. The No. 1 U.S. producer of crushed rock for road and building construction is one of Alabama's oldest and largest companies.

Vulcan traces its roots to 1909, and is a big employer in the metro area, with 435 people at the Liberty Park headquarters and hundreds more at rock quarries.

Much of that would disappear if Martin Marietta prevails. The company envisions the combined firm based in Raleigh and led by Martin Marietta executives, who have pledged to eliminate $250 million in costs by cutting duplicate jobs and departments.

Vulcan has said Martin Marietta is exaggerating the costs savings and that the government would force the combined company to sell valuable quarries at fire-sale prices. The company has rolled out its own cost-saving and revenue-enhancing plan and says it is better off on its own.

"Our board and management team remain focused on enhancing value for all Vulcan shareholders, including through the aggressive implementation of the Profit Enhancement Plan and Planned Asset Sales that we announced in February," Vulcan said in its Friday statement. "As demonstrated by our strong performance over the last two quarters, Vulcan is well positioned for growth, with superior aggregates operations and operating leverage, and we look forward to continuing to build shareholder value."

The Wall Street Journal said this afternoon the case in Delaware has been closely followed by mergers and acquisitions experts and that Strine's decision to block the bid could have broader implications for takeover strategy.